Updating debtors balances

good day i am trying to update the debtors(customers)
opening balances getting them from the old erpnext system to the new one. please help.

Perhaps this could be good start: https://erpnext.com/docs/user/videos/learn/opening-invoice-creation-tool.html

and you can refer to this as well: https://erpnext.com/docs/user/manual/en/accounts/opening-balance